Cathode ray tube



M. l.. GOEPPINGER ET AL 2,724,021

Nov. l5, 1955 CATHODE RAY TUBE NOV- 15, 1955 M. l.. GOEPPINGER Erm.2,724,021

CATHODE RAY TUBE:

Filed oct. e, 1952 :s sheets-sneer e AHPLIFYEZ INVENToR. POVLAND[..MILLER /gxx L. GoEPP/NGEIZ www iufm Novl 15. 1955 M. l.. GOEPPINGERETA'L CATHODE RAY TUBE 5 Sheets-Sheet 5 Filed OCT.. 6, 1952 -POVLAND L.NILLEQ 2,724,021 Patented Nov. 15, 1955 CATHODE RAY TUBE Max LouisGoeppinger, Sherman Oaks, and Rowland L. Miller, Hollywood, Calif.,assignors to Magnescope Corporation, a corporation of Nevada ApplicationOctober 6, 1952, Serial No. 313,312

15 Claims. (Cl. 179-1002) This invention relates generally to cathoderay tubes. In a specific aspect, it relates to machines for editingmagnetic sound record wire, tape or film. It relates, more broadly, toapparatus for determining the electromagnetic or electrostatic patternof a magnetized or charged body, utilizing a unique cathode ray tube asthe principal component of the apparatus.

A particular object is to provide an apparatus for producing a visualimage of the pattern of magnetization stored on a magnetic medium.

A further object is to provide an improved cathode ray tube adapted toproduce an optical image of an elongated section of `a sound record,whether stationary or in motion. l

Another object is to provide a cathode ray tube adapted to produce athin, ilat fan shaped cathode ray beam, and to correspondingly produce anarrow straight line image on the picture screen of the tube; and havingmeans whereby said straight line image may be distorted on one sidethereof to indicate the characteristics of a sound record or othermagnetized body being passed over the tube.

`As` a specic embodiment, the invention contemplates an improved and`simplied machine for editing a magnetic sound record tape, wire orfilm, in such a manner that any particular section of the record,requiring observation, may be located on the tape more rapidly thanheretofore possible.

Other objects will become apparent in the ensuing specification andappended drawings in which:

Fig. 1 isa view, partially in side elevation and partially in` section,of a cathode ray tube embodying the invention;

Fig. 2^is a fragmentaryplan view of the same;

Fig; 3 is a transverse sectional view taken on the line 3--3 of Fig. 1;

Fig. 4 is a transverse sectional view of the same taken on the line 4-4of Fig. 1;

Fig. 5` isl an axial sectional view of the same taken on the line 5-5 ofFig. 4;

Fig. 6 is an axial sectional view of the rear end portion of the tube;

Fig. 7 is a front View of the tube illustrating the picture screen and asound track image thereon;

Fig. S is an axial sectional` view of a cathode `ray tube embodying amodified form ofthe invention;

Fig. 9 is a fragmentary perspective sectional view of a` cathode raytube embodyingA another torm` of` the invention;

Fig. 9a is fragmentary perspective view of another embodiment of theinvention;

Fig. 9b illustrates the image obtained on the screen of the tubeembodied in Figure 9a;

Fig. 10 is aA transverse sectional view' of a cathode ray tube embodyinga further modified form of the invention, as embodied in an editingmachine;

Fig. 11 is a fragmentary plan view of the same;

2` Fig. l2 is a view of the same, partially in elevation and partiallyin axial section;

Fig. 13 is a transverse sectional view of the same, taken on the line13-13 of Fig. 12; and

Fig. 14 is a transverse sectional view of the same, taken on the lineu14--14 of Fig. 12.

Description of the cathode my tube Referring now to the drawings indetail, we have shown, as an example of one form in which the inventionmay be embodied, a cathode` ray tube forming part of an editing machinefor magnetic. tape such as that used for the sound record of soundmovies. The cathode ray tube has an evacuated envelope 9 including askirt 13 of conventional frusto-conical form, closed at its forward endby ascreen 1). The screen 10 may consist in a dished end member 11 and aluminescent coating 124 of suitable phosphors on the inner surfacethereof. End member 1l is of transparent or translucent material, andmay be of glass, as may also the skirt 13. The truste-conical skirtportion 123 of envelope 9 is interiorly coated with a conductive anodecoating A3 (e. g. graphite) to which. is connected an electric terminal15 embedded in a suitable protuberance 16 on the skirt 13.

Envelope 9 includes a barrel 17 interiorly communieatingl with the skirt13 and projecting` rearwardly therefrom. The rear end of barrel 17 ishermetically closed by acap 14 of insulating material in .which ismounted an electron gun 18. (jun 18 comprises a cathode C confinedwithin a collar shaped grid 19. A heater 21, which may be in the form ofa coiled filament, is disposed within grid 19 immediately behind cathodeC, for activating the same.

Forwardly of electron gun 18 is a primary anode A1 of conventionalannular cup form, having a central aper ture 20. Anode A1 functions in aconventional manner to` accelerate the flow of electrons from cathode Cthrough aperture 2i) to produce a cone-shaped cathode ray beam 23 ofspreading cathode rays, projected forwardly into barrel 17, centeredabout the longitudinal axis 24 of the tube. i ln a plane at right anglesto axis Z4, approximatelywhere beam 23 would intersect the wall ofbarrel 17is mounted a gate 25 in the form of a thin disc ofsheetmaterial (e. g. non-magnetic sheet metal), having an aperture 6 1nthe form of a narrow diametrical slot which passes a thin at band 22 ofrays from beam 231 Beam 22 is fan shaped, its side margins spreading as'it passes through skirt 13, so that the beam is the full width of screen10 when it strikes the latter.

From its rear extremity, where it joins` cap 14, barrel 17 provides. anannular interior wall of conductive material which constitutes an anodeA2. Anode A2 may be either of nonmagnetic sheet metal or nonmetallicsheet material, interiorly coated with a metallic film. As a preferredform of construction, anode A2 comprises a length of metallic tubing,joined at its rear end to glass end cap 14 and at its forward end joinedto a nonmetallic collar Z7 which may constitute an integral extension ofskirt 13.

. `inset into secondary anode A2 is a saddle 28, which may consist in ashort semi-cylindric section of metal tubing or formed sheet metal. Itis electrically connected to anode A2 and forms a part thereof. In itspreferred form, it may be of copper or brass sheet material, brazedy orsoldered to the wallI of the metal tube portion of barrel` 17, justforwardly of gate 25;

The central portion of saddle 28` on its inner side is flattened as at35 so as to be of paper thinness, and is provided with a window aperture39 in. the form of a narrow slot extending transversely of the. tube,parallel tothe plane of beam 22. Aperture 39 is covered by a window 40which consists in a strip of very thin nonmetallic sheet material ornonmagnetic sheet metal suitably cemented, brazed or welded to the outerwall of saddle 2S around the margins of aperture 39. Window 40 is ofminimum thickness consistent with the ability to withstand atmosphericpressure over the aperture 39 without deforming. For example, it mayfall within a range of .001-.010 inch thickness, i. e., may approach thethickness of what is usually referred to as foiL It should also bepervious to lines of magnetic flux. An example of a material that hasbeen found suitable is nonmagnetic stainless steel.

Window 40 provides a bearing seat for a magnetic tape 36 carrying asound record, and provides for the movement of tape 36 in a planeparallel to and immediately adjacent the cathode ray beam 22 and in apath extending transversely of the tube.

The flattened faces 35 of saddle 28 are positioned with reference togateaperture 26 so that beam 22 will substantially graze the edges ofthefaces 35 bordering the aperture 39. The faces 35, instead of beingdisposed in a common at plane parallel to beam 22, are preferablyslanted away from said plane, and for this purpose may Vbe slightlycurved as shown in Fig. 5. Thus the invention provides for operation oftape 36 at maximum closeness to thebeam 22, and the magnetic field ofthe sound record on tape 36 may readily pierce the window 40 which isproximate to the beam to act upon the beam 22. The function of windowaperture 39 and window 40,l therefore, is to allow the varying magneticlield of tape 36 (which may be considered as being a relatively straightline with varying degrees of magnetization along the length thereof) toact upon the extremely thin cath-V ode ray beam 22 in a manner todistort the same by widening it into aperture 39. The result is that theimage of the beam on screen which, in the absence of excitation is athin straight line as indicated at 41 in Fig.f7, becomes distorted on`its upper side into a jagged contour as indicated at 42 in Fig. 7.

Forholding the tape 36 snugly against window 40, we provide a pad 32,carried by spring arms 33 suitably mountedv on barrel 17 as by beingsecured to lugs 34 thereon.

To position the tape 36 so that its sound track is properly centeredover window aperture 39, there is provided suitable positioning meanssuch as the abutment pins 37, selectively mounted in any one of a seriesof pairs of small openings 38 in the respective end portions of saddleV28. The openings 38 are arranged on one side only, of the windowaperture 39, since the usual method of moving .the tape through saddle28 will be to pull it through by hand, keeping one edge thereofbearing-against the abutment pins 37. Y

' It may now be noted that the window 40 provides a seat or `guide forpositioning the magnetic tape insubstantial ytangency to the cathode raybeam 22. The term .substantial tangency is herein ufed in a somewhatbroad sense of immediate adjacency, face to face, of the magnetic tapeand the plane of beam 22. Actually. where the Vwindow 40 is ofcylindrical curvature as shown, so 'as to impart a correspondingcurvature to the tape, there Electrical circuit Our improved cathode raytube, as embodied in any selected apparatus, is combined with otherelectrical components for energization to produce `the cathode ray beam.Heater 2l is energized by an A battery 43, connected to its respectiveterminals by conductors 44, v45. Grid 19 is connected, by a conductor46, to the negative side of a B battery 47. Cathode C is connected, by aconductor 48, to a cell of B battery 47 closely adjacent to the negativeside thereof. Primary anode A1 is connected by aV conductor 49 to Bbattery 47 somewhat farther toward the positive side thereof. The thirdand final anode A3, consisting in the interior conductive coating ofskirt 13, is connected through a conductor 51 to the positive side of Bbattery 47 (or at a point near the positive side, selected inVaccordance'with the exact potential to be irnpresied upon coating A3).

it will now be apparent that, with respect to cathode C, grid 19 isslightly negative, Whereas anodes A1, A2 and A3 are all positive withprogressively increasing po'- tentials, whereby each of these anodes, insuccession, exert a pull against the vnegatively charged electronsstreaming from cathode C, to drive the cathode ray beam 22 against thescreen 10.

Operation of the tube We will first ydescribe the general operation ofthe tube as a cathode ray tube. Cathode C, heated by the heater 21, willdischarge electrons in all directions 'through opening 20, theseelectrons being repelled bythe negative charge on gridl 19 so as to beaccelerated toward the narrow slotaperture 26 of gate 25 in the form ofconical spray. This spray of electrons is drawn through the narrow gateaperture 26 by the attraction of the positiv electrostatic charge onanode A2.

As the cathode ray spray 23 meets the gate 25, a large number of theelectrons at the upper and lower sides of the spray respectively,V areintercepted by the gate 25 and are drained ol through conductor 50 tothe Bfbattery 47. Thus only the central portion of the spray 23, inwhich the electrons are highly-concentrated because of :he repulsiveaction of the outer layers of the electrons in the beam, is allowed totravel through the aperture 26, and the extremely thin at beam 22,emitted from Vthe aperture 26 consists in this concentrated centralportion of the spray 23. Y.

VThe anode A3, the conductive coating within envelope 9, produces anelectrostatic attractive field which draws .he electrons of thev beam 22past window 40 and accelerates them in thetravel toward the screen 10.

Referring now to Fig. 1, the thin fiat beam 22 is fan shaped asindicated by the broken lines indicating the lateral margins thereof inFig. l. yThis fan shaped beam 22 produces an image on screen 10 in theform of a relatively thin line extending diametrically across the screenfrom side to side thereof.

The magnetic fields produced by the recording'on tape 36 penetrate thewindow 40. Thus the electrons in the cathode-ray beam pass through thesefields in their path a visual image of Athe sound track ontape 36, witheach variation in intensity in the sound being indicated by a peak onthe upper side of image 42.

The above mentioned tangent relation between the sound record tape andthe cathode ray beam 22 provides for maximum modulating action by themagnetic record upon the cathode ray beam, in that it disposes thegeneral plane of the magnetic record substantially in the plane .Y

of a flattened side of the beam so that all portions ofthe width of thesound record are of substantially equal eiec- Y tiveness which would beobtained'if the ribbon were disposed in a plane at right angles to theplane of the beam.`

As an example of one classV of apparatus in which' the invention isparticularly useful, the illustration of the tape 36 and reels 61, 62 inconnection with the cathode ray tube, may be viewed as a schematicillustration of components of an editing machine of which the cathoderay tube constitutes the major component. Any suitable means may beutilized for driving one of the reels (e. g. the reel 62), to cause thetape 36 to move as indicated by the arrow in Fig. l0, transversely ofthe tube and directly above the thin llat cathode ray beam 22 and thewindow aperture 39. Such drive may, for example, be transmitted to reel62 through a shaft 91 from an electric motor 52 suitably energized froma current source 53 under the control of the operator through a manualswitch 54. Motor 52 is preferably a reversible motor, and switch 54 atwo-way switch, for controlling the operation of the motor selectivelyin either forward or reverse directions through respective circuits 55,56. Thus the tape may be backed up when desired.

The editing apparatus may also include a sound reproducing unitincluding an electromagnetic pick-up 57 associated with sound tape 36for excitation by the sound track thereon, a suitable amplifying unit 58of any satisfactorily conventional design, and a dynamic speaker 59,energized through the amplifier 58.

Operation of editing apparatus ln the operation of the editing apparatusschematically indicated in Fig. ltl and Fig. ll, the operator, seated infront of the screen and viewing the image 42 thereon, causes` the tape36 to travel across the window 40 and aperture 39, controlling themovement of the tape by the manual switch S4. Allowing the tape tonormally have a continuous forward full speed travel as indicated by thearrow, he listens to the sound issuing from the speaker 59, andsimultaneously watches the fluctuations of image 42, relating them tothe fluctuations in sound. lf the pick-up 57 is located at one side ofthe tube, as shown, the visual image of an instantaneous sound willoccur at the corresponding side of screen lil at the instant it is beingdelivered in audible form from speaker 59. When the operator hears anote or any other sound which in his opinion should be located on thesound record, he opens the switch 54 to arrest the travel of tape 36,and, if necessary, momentarily reverses the drive to back up" the tapeto a position where the visual image of the unwanted sound reappears onthe screen (assuming it has travelled off the screen in the meantime).The image 42 maythen be frozen upon screen 10 in a stationary condition.By manually shifting the tape 36, the operator can bring the image ofthe selected sound to the center of screen it), thus bringing thecorresponding point on the sound tape 36 to the center of saddle 28.This point can be accurately indicated in any suitable manner, using theindicator mark 60 as a guide for accurate location of the mark, so thatsubsequently the tape may be severed at the indicating mark thereon, forediting purposes. Actually, the severed portion of the tape willordinarily be embraced between a pair of marks on the tape showing therespective limits of the section of tape that is to be removed.

During this process of arresting the movement of the tape and placingindicating marks thereon, the operation o'f the cathode ray tube iscontinued, so that the visual image 42 will remain on the screen l0. Asthe tape is shifted manually in one direction or the other, to bring, insuccession, the respective limits of the undesirable sound opposite theindicator mark 60, the visual image of the sound will move, in step withthe movement of the tape, so that the limits thereof may be accuratelydetermined by registration with the center of screen lil, or with anindicator mark 60 on the screen 10, properly related to indicator mark60 on seat 33. lt will be understood that, before shifting the tape overto the marking point, the limits of the selected sound on-the recordwill be determined by reference to the limits of the same sound in itsvisual image 42.

It will now be apparent that the invention provides an apparatus wherebya visual image of a. selected sound on a sound track can be manipulatedmanually by slow motion to a predetermined position where, by referenceto said visual image, the respective limits of the corresponding portionof the sound record can be accurately marked upon the sound tape,whereas the corresponding audible sound cannot be maintained throughsuch slow motion manipulation of the tape, for the reason that thereproduction of the audible sound depends upon the rapid and continuedmovement of the tape at a predetermined, uniform speed, past the pick-up57. This movement of the tape is so rapid as to make it impossible topinpoint the limit of the particular section of the sound track whichcorrespond to the selected sound heard in the loud speaker 59.Accordingly, after having first located the limits of the selected soundupon the visual image 42, the operator then dispenses with the audiblesound and utilizes simply the visual image 42 in order to fix thelocation of the selected section of the sound record by means ofmarkings on the tape 36.

Gne of the important uses of an editing machine of this type is inlocating certain accent sounds in a sound record, such as for examplethe impact of the toe of a tap dancer doing a tap dance routine, or thesound of a gunshot. Obviously it is quite important that such sounds besynchronized exactly with the visual image of the dancers toe contactingthe stage or of the gun firing the shot, in the assembling of the soundtrack on the iilm, and the invention provides a very easy method ofdoing this. Another' possible use of the apparatus is in detecting anddeleting undesirable sounds from a sound record.

Other applications of the invention Other useful applications of theinvention will suggest themselves to those skilled in the art, and it ismy intention to cover various applications of the invention to usesother than sound record editing apparatus. For example, it is possibleto test the crystalline structure of wires, rods, cables, etc., bypassing them longitudinally through the saddle 28, in contact with orclose proximity to Window 4i). By suitably causing an alternatingelectric current to ow through the wire, rod or the like, magneticfield, varying in accordance with variations in the crystallinestructure of the wire, rod or the like, may be produced, and thisvarying field, penetratingwindow 40, will produce a distortion of theimage 41 on screen 10, having recog nizable characteristics such as toindicate flaws, etc., in the wire, rod, cable or the like. In the eventit is desired to determine the state of magnetization or a lack ofmagnetization of an object, the object may simply be passed over window40 without being subjected to an electric current, resulting in a visualimage on screen 10 disclosing the variations in magnetization. Byvarying the shape of saddle 28 to receive a physical object such as acasting or the like, the magnetic characteristics thereof may bedetermined by moving the object in close proximity to window 40 so as tosuccessively present different portions of the surface area of theobject thereto.

Fig. 8 illustrates a modified form of the invention Wherein, instead ofthe means for reshaping a round beam into a thin flat beam, there isprovided means for producing a thin7 needle-like beam 22a, together withmeans to cause said beam 22:1 to sweep back and forth across'the tube inan axial plane 24 so as to produce an image on screen 10 in the form ofa diametral line 41 which is distorted to produce an image 42corresponding to the variations in a sound record track on tape 36.

For producing the sweep of beam 22a, there is provided a conventionalcontrol set of deilection coils in ring 70 encircling the barrel 17 andenergized by a conven tional sweep circuit component, indicatedschematically at 71, operable to alternately deflect the beam first toone side and then the other. i The control ring 70 is so placed as tocause the sweep to occur in the axial-plane 24', parallel to andimmediately adjacent the window 40. As the'beam sweeps back and forth,it is widened in a direction at right angles to plane 24', with thewidening action varying throughout the path of sweep, in accordance withthe variations in intensity in the electromagnetic or electrostaticiieldof the tape 36 or other object passing across window 40. A suitableanode A1, of conventional form, for shaping the cathode ray beam into aslender needle form, is utilized instead of the anode A1 of the abovedescribed form of the invention.

Fig. 9 illustrates a further modification wherein a cathode ray beamissuing from a gun 1817 passes through a primary anode Ab, thencebetween a pair of Variable potential electrostatic sweep-control plates75 for causing the beam to sweep from side to side in a plane parallelto and midway between a pair of fixed-potential anode plates lA2,thusproducing a diametral line image on screen 10 which is varied intexture by the control parts 28, 38, 40, etc., all corresponding to thesame parts in Fig. 1.

Fig. 9a illustrates an arrangement in which saddle 28 blocks onlyone-half of the beam 23, allowing the other half to spread in the shapeof a half cone, producing an image 41" on screen 10 (Fig. 9b) in theshape of a 180 segment of a circular disc of light. Image 41 has itsnormally straight upper margin modified by response to a sound tape, asindicated at 42".

Fig. 12 illustrates a further modified form of the invention. Aconventional electron gun 18 is utilized, as in Fig. 1. Forwardly ofelectron gun 18 is a primary anode A1 which comprises a pair of plates29 the rear portions of which are spaced relatively close to anddisposed on opposite sides of the transverse axial plane of the tube.Plates 29 extend to the full width of the barrel 17 from the widthindicated in the cross sectional view shown in Fig. 14. The rearextremities of plates 29 are attached to a gate 25, which has a narrowaperture 26 in the form of a transverse slot bisected by the axialplane. The cathode ray beam issuing from cathode aperture 20 in the formof a spreading cone 23 of cathode rays, is reshaped by gate 25, as theypass through aperture 26, into a beam of iiat ribbon form, indicated bythe broken lines 22C in Fig. l2.

Forwardly of primary anode A1 is a secondary anode A2 which includes ananode duct in the form of a tube of shallow rectangular cross sectionincluding transverse wall portions 30, extending transversely of barrel17, parallel to axial plane and equally spaced above and below the same,and including relatively narrow side walls 31 joining the transversewalls 30. Tube 30, 31 is of electrically conductive material, such asmetal (e. g., copper, stainless steel, etc.). The secondary anode A2also includes the barrel 17, which is constructed of metal tubing or ofglass tubing with a conductive coating on its inner face. The secondaryanode A2 also includes a pair of shields 32 and 28 which extendtransversely of barrel 17 in symmetrical relation to the axial plane andare equally spaced above and below said plane, with their centralportions closely spaced to define a flat shallow pass 39 extending thefull width of barrel 17 as indicated in the ,cross sectional view inFigure 14. Shields 32 and 28 are of channel section in an axial plane ofthe tube at right angles to the axial plane. In a transverse section ofbarrel 17 (in a plane normal to the tube axis) they deline parallelstraight lines.

Shields 32. 28 may be of non-magnetic sheet metal or of non-metallicsheet material, interiorly coated with a metallic film. They function4to intercept all portions of beam 22e except the thin at centralportion 22 which passes on to the screen. shields 28, 32 are drained offthrough return circuit 50, back to potential source 47.

' In` other respects, the tube of Fig. 12 is like that of Fig. 1, andcorresponding reference numerals are used to designate the same.

The electrons which strike While the descriptions of the embodiments ofthe invention all show magnetic tape brought into contact with and beingmoved with the tape extending transversely to the path of thecathode-ray beam in the tube, it should be appreciated that this is notto be construed as a limitation. The magnetic tape may also be brought,for example, into and out of contact with the window 40V with the tapeextending in the same direction as the cathoderay beam to effectivelydisplay the magnetic pattern recorded on the tape. This type ofoperation may be employed where information is recorded in the form ofbinary coded pulses on several parallel longitudinally extending trackson the tape. The tape may be brought into and out of contact with thewindow, for example, over a fairly narrow rod or roller, in order thatonly one set of aligned pulses may be seen at a time. In effect, thepresent invention may be used with magnetic tape as a visual readinghead for magnetically recorded information, regardless of the directionof recording, to display the information recorded in any desired portionof the recording medium, whether it is moving or stationary, by bringingthe recording medium into such proximity with the cathode-ray beam ofthe invention that no guiding structure for lines of ux emanating fromthe recording medium is required to cause them to deflect the cathoderaybeam.

Accordingly, there has been shown and described herein a novel anduseful cathode-ray tube which can provide a visual display of theinformation recorded on a section of a magnetic medium brought intoproximity with the tube without employing any auxiliary equipment. Suchdisplay is provided whether the magnetic medium is stationary or inmotion.

We claim:

1. The combination with a magnetic recording medium on which signalshave been recorded on a cathode-ray tube including an evacuatedenvelope, a screen at one end of said envelope, means at the other endof said envelope for generating a cathode-ray beam having asubstantially elongated rectangular cross-sectional area, means fordirecting said beam toward said screen and means to which said recordingmedium is applied to act upon said cathoderay beam with the magneticfield from signals recorded thereon, said means comprising a surface insaid evacuated envelope wall made of sheet material substantiallypervious to lines of magnetic ux and which maintains said evacuatedenvelope sealed, said sheet material being positioned in said tube to bealong the path of said beam toward said screen, and to separate saidbeam from said storage medium.

2. In apparatus for displaying signals recorded on a magnetic storagemedium a cathode-ray tube having an evacuated envelope, a screen at oneend of said envelope, means at the other end of said envelope forgenerating a cathode-ray beam, means for shaping said beam to have asubstantially elongated cross-sectional area, means for directing saidbeamin a path toward said screen and means to which said medium isapplied to act upon said cathode-ray beam with the magnetic field fromsignals recorded thereon, said means comprising a surface in saidevacuated envelope wall made of sheet material substantially pervious tolines of magnetic flux and which maintains said evacuated envelopesealed, said sheet material being positioned in said tube t0 be alongthe path of said beam toward said screen and to have one of its surfacessubstantially touching the long side of said beam and its oppositesurface substantially in contact with said storage medium.

3. Apparatus as recited in claim 2 wherein said sheet material is madeof non-magnetic stainless steel.

4. Apparatus as recited in claim 3 wherein said means for acting onAsaid cathode-ray beam includes two sheet material surfaces in saidenvelope wall which are located opposite one another.

5. In apparatus for displaying information recorded on magnetic tape acathode-ray tube havingA an evacuated envelope, a screen at one end ofsaid envelope, means at the other end for generating a cathode-ray beam,means for shaping said beam to have an elongated substantiallyrectangular cross-sectional area, means for directing said beam in apath toward said screen, and means, including means` in said tubeagainst which said tape is applied, to produce a visible pattern on saidscreen representative of the information recorded on the prtion of the.tapebeing applied, said last-named means comprising an aperture inr saidenvelope, a thin sheet of material sealing said aperture, said materialbeing pervious to` lines of magnetic flux and being positioned in thepath` of and having one. surface proximate to said rectangular beam,said tape being applied to said opposite surface.

6. In apparatus for displaying signals recorded on a magnetic storagemedium a cathode ray tube comprising an evacuated envelope including abarrel, a skirt, and a screen at the outer end of said skirt; anelectron gun in said barrel, arranged to project a bundle of cathoderays toward said screen; a primary anode; means for reshaping saidbundle into a thin, at beam impinging on said screen to produce a visualimage of linear form; a secondary anode including a saddle memberprojecting inwardly from the wall of said barrel and having an elongatedwindow aperture extending chordally with reference to said barrel walland parallel and close to the plane of said flat beam; and a window ofthin, nonmagnetic sheet material covering and sealing said windowaperture and forming part of said envelope, said window providing a seatfor guiding the movement of said magnetic medium past said windowaperture, and being permeable to the magnetic fields of the signals onsaid medium whereby said signals are visually reproduced by distortionof said image.

7. Apparatus as defined in claim 6 wherein said flat beam plane isdisposed closely adjacent an axial plane of said tube, whereby saidimage line is positioned sub stantially as a diameter of said screen,and wherein said Window is substantially tangent to said plane so as tosupport said tape in a plane substantially coincident with said beamplane.

8. Apparatus as delined in claim 6, wherein said skirt is provided onits inner surface with a conductive coating constituting a third anodeof higher potential than said secondary anode, for further acceleratingsaid beam.

9. In apparatus for displaying signals recorded on magnetic tape acathode-ray tube having an evacuated envelope including a barrel, askirt, and a screen at the outer end of said skirt; an electron gun insaid barrel, arranged to project a bundle of cathode rays toward saidscreen; a primary anode; means for reshaping said bundle into a thin,flat beam impinging on said screen to produce a visual image of linearform; a secondary anode including a saddle member of semi-cylindricallyarched form, arranged in reentrant relation to the barrel, with its axistransverse to the tube axis and with its central portion substantiallytangent to a plane of said tube axis and having a window aperture ofslot form extending substantially diametrically of said barrel; and awindow of thin, nonmagnetic sheet material covering and sealing saidwindow aperture, arched inwardly across the plane of said aper ture andtangent to the plane of said flat beam, said window providing a seat forfacilitating movement of a magnetized tape past said window aperture,and being permeable to the magnetic elds of the signals recorded on saidtape whereby said fields are visually reproduced by distortion of saidimage.

10. Apparatus for displaying signals as recited in claim 9 wherein saidmeans for reshaping said bundle into a thin, ilat beam impinging on saidscreen to produce a visual image of linear form includes a pair of gatemembers disposed within and transversely of said barrel a substantialdistance forwardly of said primary anode, said to gate` members beingspaced to deline a narrow pass4 dis,- posed diametrically of said barreland functioning to reshape said cone into a thin, flat beam impingingupon said screen to produce a visual image of linear form, said saddlemember being disposedl slightly forwardly of said gate members.

11. In apparatus as recited in` claim 9 wherein said primary anodeincludes a conductive coating, on the inner Wall of said barrel andfurther includes va pair of shield members defining a pass of restricteddepth for passage of a central layer of said beam while interceptingouter layers of said beam, whereby to reduce said beam in thickness sothat the. beam as it strikes` said screen will be thin and broad,producing a visual image in the,V form of a straight line on the screen.

12. In apparatus for displaying signals recorded on magnetic tape acathode ray tube having an evacuated envelope including a skirt, abarrel, and a screen at the forward end of the skirt; an electron gun insaid barrel, arranged to project cathode rays toward said screen; aprimary anode interposed between said gun and said screen slightlyforwardly of said gun, adapted to bend said rays into a cone ofspreading cathode rays; a gate comprising a disc disposed in a plane atright angles to the longitudinal axis of the barrel, a substantialdistance forwardly of said primary anode, said barrel being a sheetmetal tube, electrically connected to said gate members and cooperatingtherewith to constitute a second anode, said disc having a diametricallydisposed narrow slot constituting a pass for reshaping said cone of raysinto a thin, flat beam impinging upon said screen to produce a visualimage of linear form; a saddle member of semi-cylindrical arched formdisposed slightly forwardly of said gate and constituting a reentrantportion of the exterior wall of the tube and having therein a windowaperture of slot form extending substantially diametrically of saidbarrel and parallel and immediately adjacent to the axial plane of saidpass; and a window of thin, nonmagnetic sheet material having acylindrical curvature corresponding to that of said saddle membercovering and sealing said window aperture and forming part of saidenvelope, said window providing a seat for guiding the movement of saidtape past said window aperture, and being permeable to the magneticiields from signals recorded on said tape whereby said fields arevisually reproduced by distortion of said image.

13. In apparatus as defined in claim 12 wherein said saddle member hasend portions projecting beyond the sides of the tube, and positioningstops adjustably carried by said end portions for adjustment laterallyof the axis of the saddle, said saddle axis extending transversely withreference to the longitudinal axis of the tube.

14. In a magnetic sound tape editing machine, an evacuated envelopeincluding a barrel, a skirt, and a luminescent screen at the outer endof said skirt; an electron gun insaid barrel arranged to project abundle of cathode rays toward said screen; a primary anode; means forreshaping said bundle into a thin, fiat beam impinging on said screen toproduce a visual image of linear form; an arched saddle memberconstituting a reentrant portion of the wall of said barrel and having awindow aperture of slot form extending chordally with reference to saidbarrel wall; a window of thin non-magnetic sheet material covering andsealing said window aperture and forming part of said envelope, saidwindow providing a seat for guiding the movement of a magnetic Soundtape past said window aperture, and being permeable to the magneticfield of said tape whereby said iield will be visually reproduced bydistortion of 'said image; and tape reels for supporting a sound tape sothat a web thereof, extending between said reels, may travel past andupon said window, transversely of the tube axis.

l5. In an apparatus for producing a visual image of a substantial lengthof a magnetized record on an elongated recording medium, a cathode raytube comprising an evacuated envelope including a skirt, a barrel, and ascreen at the forward end of said skirt; an electron gun in said barrel,arranged to project a bundle of cathode rays toward said screen; meansfor reshaping said bundle into a thin, flat beam impinging on saidscreen to produce a visual image of linear form; said barrel having areentrant'wall portion providing an elongated space l extendingtransversely of the barrel and open to the exterior thereof, wherebysaid magnetized recording rnedium can be inserted into and passedthrough said space, said lreentrant wall portion having a bottomportion, and of such thinness as to be permeable to the magnetic eld ofsaid tape, and of elongated form, disposed chord- 12 ally with referenceto the barrel and substantially tangent to'said beam, whereby themagnetic sound record upon said tape can be disposed in substantialtangency so as to be visually reproduced by distortion of said screenim` age.

References Cited in the iile of this patent UNITED STATES PATENTS2,164,302 Barnes et al. July 4, 1939 2,165,307 Skellett July 11, 19392,185,138 Woli Dec. 26, 1939 2,594,731 Connolly Apr. 29, 1952'2,608,669v Hurvitz Aug. 26, 1952

